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Discussion Starter #1
Hello all,

So I've pulled out my C12 to try and fix a few issues I've had with it, and one that I've had trouble finding info about is the boiler water inlet valve. This is a check valve that is connected directly to the boiler and is fed by a track-side water pump (or more commonly now a spray bottle with the proper fittings attached).

My issue is that when the nut is unscrewed from the place where you attach the water pump, a pretty constant drip leaks from the pipe suggesting that the check valve is not seating correctly. I opened up the check valve to see whats up (pictures attached). Besides the cap, there is the expected ball bearing, but I do not see any rubber seal for it to nest on or a spring to push it down and seat the bearing.

My questions for folks familiar with these check valves: Is there anything missing from my valve (i.e. a gasket or spring)? Besides cleaning out possible water scale around where the bearing sits, is there anything else I can do to promote a better seal?

P.S. That is not mold you see in the picture, but fire extinguisher dust from a near accident a while back with alcohol over spill... I'll be giving her a good clean after I fix a few things.

Thanks folks,
Mike
 

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Mike.........it is a gravity/steam pressure check valve. The ball looks clean so cleaning the seat
without making any marks where the ball rests and you should be good to go. A small amount of vinegar in the distilled water might also help with any deposits .
 

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I don't believe anything is missing. No spring is needed as it is the water pressure that pushes the ball against the seat. No gasket is used either. The metal should be shaped such that the ball seats against it perfectly. They can leak a wee bit normally, but not much.

Some will tell you to polish the seat and then get TWO new balls. Put one in the unit and then put a wood dowel on it and "gently tap" to dowel with a small hammer to re-shape the seat to fit the ball. Then throw THAT ball away! Put the other ball in and replace the cap.

The only problem is that there is very little metal available in these tiny things to wear off in polishing it and you could remove too much, or make the seat too flat across such that tapping the ball against it will not deform the remaining metal properly to make the ideal seal.

I cannot tell you how hard to "gently tap" the ball to form the seal... that I a matter of "feel", but I can't describe the feel to use.
 

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Discussion Starter #5
Sal & Semper,

Thanks for the info, I'll give it a go with cleaning it up without marring the seat and see how it performs.

Additional question not to do with the valves... this just came up.

I noticed when moving my loco on a test rail that it will move forward a few inches and the wheels will lock and not allow it go go further, the same if pushing it backwards. Does this sound like the wheel slides/linkage may be misaligned and preventing a full cycle?
 

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Possibly, but it could also be that the cylinders have a good seal and it is just a compression lockup. Try putting the valve gear in both Fwd and Rev to see if that makes any difference (just trying to release the compression).
 

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Discussion Starter #7
Possibly, but it could also be that the cylinders have a good seal and it is just a compression lockup. Try putting the valve gear in both Fwd and Rev to see if that makes any difference (just trying to release the compression).
Thanks again!

My loco has no Johnson Bar/lever for fwd/rev, you just push it in a direction to set the linkage and it just continues in that direction. So after a good amount of pushing it back and forth it finally started to make full revolutions. Good call on the compression lockup!

-Mike
 
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